You might not be here without the solstices & seasons

On December 21, the sun hugged the horizon. For those in the Northern Hemisphere, it seemed to barely rise before it swiftly set. For months, the orbs arc across the sky had been slumping, shortening each day. The winter solstice marks the shortest day of the year, before the sun reverses course and climbs higher into the sky. This is a good opportunity to imagine what such a day might look like if we had evolved on another planet where the sun would take a different dance across the sky. You might want to feel thankful for the solstices and seasons we do have, or we might not be here to witness them at all.

The solstices occur because most planets do not spin upright, or perpendicular to their orbits. The earth, for example, slouches 23.5 degrees on a tilted axis. This leaves the planets North Pole pointed toward the North Star over relatively long periods of time, even as earth makes its year-long migration around the sun. That means the Northern Hemisphere will spend half the year tilted slightly toward the sun, bathing in direct sunlight during summers long, blissful days, and half the year cooling off as it …read more